CYP450 phenotyping and metabolite identification of quinine by accurate mass UPLC-MS analysis: a possible metabolic link to blackwater fever

BACKGROUND: The naturally occurring alkaloid drug, quinine is commonly used for the treatment of severe malaria. Despite centuries of use, its metabolism is still not fully understood, and may play a role in the haemolytic disorders associated with the drug. METHODS: Incubations of quinine with CYPs 1A2, 2C9, 2C19, 2D6, and 3A4 were conducted, and the metabolites were characterized by accurate mass UPLC-MS(E) analysis. Reactive oxygen species generation was also measured in human erythrocytes incubated in the presence of quinine with and without microsomes. RESULTS: The metabolites 3-hydroxyquinine, 2’-oxoquininone, and O-desmethylquinine were observed after incubation with CYPs 3A4 (3-hydroxyquinine and 2’-oxoquininone) and 2D6 (O-desmethylquinine). In addition, multiple hydroxylations were observed both on the quinoline core and the quinuclidine ring system. Of the five primary abundance CYPs tested, 3A4, 2D6, 2C9, and 2C19 all demonstrated activity toward quinine, while 1A2 did not. Further, quinine produced robust dose-dependent oxidative stress in human erythrocytes in the presence of microsomes. CONCLUSIONS: Taken in context, these data suggest a CYP-mediated link between quinine metabolism and the poorly understood haemolytic condition known as blackwater fever, often associated with quinine ingestion

Supplementary data for article: Opsenica, I. M.; Verbić, T. Ž.; Tot, M.; Sciotti, R. J.; Pybus, B. S.; Djurković-Djaković, O.; Slavić, K.; Šolaja, B. A. Investigation into Novel Thiophene- and Furan-Based 4-Amino-7-Chloroquinolines Afforded Antimalarials That Cure Mice. Bioorganic and Medicinal Chemistry 2015, 23 (9), 2176–2186. https://doi.org/10.1016/j.bmc.2015.02.061

Supplementary material for: [https://doi.org/10.1016/j.bmc.2015.02.061]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1691

Investigation into novel thiophene- and furan-based 4-amino-7-chloroquinolines afforded antimalarials that cure mice

We herein report the design and synthesis of a novel series of thiophene-and furan-based aminoquinoline derivatives which were found to be potent antimalarials and inhibitors of b-hematin polymerization. Tested compounds were 3-71 times more potent in vitro than CQ against chloroquine-resistant (CQR) W2 strain with benzonitrile 30 being as active as mefloquine (MFQ), and almost all synthesized aminoquinolines (22/27) were more potent than MFQ against multidrug-resistant (MDR) strain C235. In vivo experiments revealed that compound 28 showed clearance with recrudescence at 40 mg/kg/day, while 5/5 mice survived in Thompson test at 160 mg/kg/day

CYP450 phenotyping and accurate mass identification of metabolites of the 8-aminoquinoline, anti-malarial drug primaquine

<p>Abstract</p> <p>Background</p> <p>The 8-aminoquinoline (8AQ) drug primaquine (PQ) is currently the only approved drug effective against the persistent liver stage of the hypnozoite forming strains <it>Plasmodium vivax</it> and <it>Plasmodium ovale</it> as well as Stage V gametocytes of <it>Plasmodium falciparum</it>. To date, several groups have investigated the toxicity observed in the 8AQ class, however, exact mechanisms and/or metabolic species responsible for PQ’s haemotoxic and anti-malarial properties are not fully understood.</p> <p>Methods</p> <p>In the present study, the metabolism of PQ was evaluated using <it>in vitro</it> recombinant metabolic enzymes from the cytochrome P450 (CYP) and mono-amine oxidase (MAO) families. Based on this information, metabolite identification experiments were performed using nominal and accurate mass measurements.</p> <p>Results</p> <p>Relative activity factor (RAF)-weighted intrinsic clearance values show the relative role of each enzyme to be MAO-A, 2C19, 3A4, and 2D6, with 76.1, 17.0, 5.2, and 1.7% contributions to PQ metabolism, respectively. CYP 2D6 was shown to produce at least six different oxidative metabolites along with demethylations, while MAO-A products derived from the PQ aldehyde, a pre-cursor to carboxy PQ. CYPs 2C19 and 3A4 produced only trace levels of hydroxylated species.</p> <p>Conclusions</p> <p>As a result of this work, CYP 2D6 and MAO-A have been implicated as the key enzymes associated with PQ metabolism, and metabolites previously identified as potentially playing a role in efficacy and haemolytic toxicity have been attributed to production via CYP 2D6 mediated pathways.</p